I think when you get shimmering in the distance there are two things happening. First, the game is still not final and I think there might be a few things with shaders that may require a closer examination. Second, even if the first isn't true it is almost certainly a case of eating your cake and having it too. What I mean is, you want all of the eye candy and you want it to still look good in every case. So you set your graphics details up to maximum and then when aberrations occur you think its the game, when instead its a user fault.
If you start with your graphic settings as I suggested for FGBullet in this thread, then you may see what I am talking about. Always keep Environment OFF. Turn that on when you are showing off the game, but not while playing. If you move the sliders you will see the terrain textures flashing as you make changes. The flashes are brief and probably the result of updating textures, polys, and vertices, but that's not really important. The important thing is for you to find a place on the map where you can see the terrain off into the distance. Adjust the sliders to the point where the distant trees do not shimmer/flash/or dance. This is the point at which your card is about maximized on handling those features. You will want to back off of that position by about 15%, to leave room for things like multiple airplanes and vehicles.
If you think you have a powerful system, then think again. Even the vaunted 1080 will not play this game in every situation at 60fps. Ain't gonna happen. If you doubt me, then go sit at the refinery and start blowing up fuel structures with the arena controls. When you get down to 13fps you will know the reality of the situation.